Chapter 6 Acids, Bases, Salts, Solubility Acids, Bases, Salts, Solubility, And stuff like that!
TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids,...
-
date post
21-Dec-2015 -
Category
Documents
-
view
219 -
download
2
Transcript of TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids,...
![Page 1: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/1.jpg)
TOPIC V: Ions in Aqueous Solutions
LECTURE SLIDES:
• Precipitation Reactions• Solubility : Acids, Bases, Salts• Net Ionic Equations• Acid/Base Reactions• Gas Forming Reactions
Kotz & Treichel, Chapter 5, Sections 5.1- 5.6
![Page 2: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/2.jpg)
Chapter Five Double Replacement Reactions in Aqueous
Solutions:AB(aq) + CD(aq) AD + CB
A) Precipitation reactionsB) Acid/ Base reactionsC) Gas Formation reactions
NOTE: All these reactions are often represented by a balanced “net ionic equation” which we will meet as we look at these types!
![Page 3: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/3.jpg)
“The Game Players”
Generally, two aqueous solutions, each containing a 100% ionized solute, a “strong electrolyte,” are required to commence action in any of these three types of reactions.
In order to appreciate what is happening, we mustexamine all terms ...
AB(aq) A+(aq) + B- (aq)
CD(aq) C+(aq) + D- (aq)
![Page 4: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/4.jpg)
“AQUEOUS SOLUTIONS”
“AQUEOUS SOLUTION” = homogeneous mixture of some solute in a specific solvent, water
HOMOGENEOUS: uniform composition throughout, one phase. Liquid solution: transparent, no boundaries, layers, bubbles or solid particles visible.
![Page 5: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/5.jpg)
solid solute
liquid solute
gas solute
water SOLVENT
aqueous SOLUTION
+
![Page 6: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/6.jpg)
“Strong Electrolytes”
Double Replacement reactions in aqueous solutions occur when both reactants are “100% ionized” in aqueous solutions.
H2OAB ----------> A+
(aq) + B-(aq)
H2OCD ----------> C+
(aq) + D-(aq)
The solutes described above are called “strong electrolytes”. To better understand this concept, let’s consider the following demonstration and video clip.
![Page 7: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/7.jpg)
SOLUTES TO BE BE TESTED AS ELECTROLYTES:
salt (NaCl), sugar (C12H22O12), hydrochloric acid (HCl), acetic acid (vinegar, HC2H3O2), ammonia (NH3), alcohol (CH3CH2OH), sodium hydroxide (NaOH)
We are going to see what happens to the demo light bulb when the electrodes are immersed in first pure water, and then into water containing these solutes.
DEMONSTRATION!!!
Compounds which form ions in water solution are considered “electrolytes” because their presence allows the solution to conduct electric current.
![Page 8: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/8.jpg)
If there are NO ions present in solution, the liquid or solution will NOT conduct a current and the light bulb will not “light up”
If the solute present in the solution is completelyionized, the solution will readily conduct a currentand the light bulb will “light up brightly”
If the solute is ionized to a small extent (“mostly molecular”), then the light bulb may “glow faintly”
![Page 9: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/9.jpg)
Summary, Results:
pure water
salt water
HCl in water
Acetic Acid in Water
alcohol in water
NaOH in water
Ammonia in water Sugar in Water
![Page 10: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/10.jpg)
We can sort out our results into three categories, based on our observations:
Strong electrolytes: allow current to flow through solution: NaCl, HCl, NaOH, all 100% ionized in solution
Weak Electrolytes: allow a small amount of current to flow through solution: HC2H3O2 and NH3 (aq) as“NH4OH”, small amount of ionic presence, mostly“molecular” in nature
Non Electrolytes: No ions, no current: molecular innature: water, alcohol (CH3CH2OH), sugar (C12H22O12).
![Page 11: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/11.jpg)
Strong Bases: Soluble Metal hydroxides: NaOH, KOH
STRONG ELECTROLYTES: REACTANTS, DOUBLE REPLACEMENT REACTIONS
Salts: metal or ammonium cation , monatomic or polyatomic anion: NaCl K2SO4 AgNO3 NH4BrO3 CuI2
Strong Acids: H written first in the formula, Strong: HCl, HBr, HI, H2SO4, HNO3
![Page 12: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/12.jpg)
Salts in water: Cation, not H+, Anion, not OH-
NaCl(s)H2O Na+
(aq) + Cl-(aq)
H2O
H2O
H2O
Cu(NO3)2(s) Cu2+(aq) + 2 (NO3)-(aq)
Al2(SO4)3(s) 2 Al3+(aq) + 3 (SO4)2-
(aq)
K3PO4(s) 3 K+(aq) + PO4
3-(aq)
![Page 13: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/13.jpg)
BASES IN WATER: Cation not H+; Anion: OH-
KOH(s)H2O
K+(aq) + OH-
(aq)
NaOH (s)H2O Na+(aq) + OH-
(aq)
NH3(g) + H2O(l) NH4+
(aq) + OH-(aq)
![Page 14: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/14.jpg)
ACIDS IN WATER: H+ Cation; Anion, not OH-
H2SO4(l)H2O
H+(aq) + HSO4
-(aq)
100%
HCl(g)H2O
H+(aq) + Cl-(aq)
HSO4-(aq)
H2O
50%
H+(aq) + SO4
2-(aq)
HC2H3O2(aq) H2O H+(aq) + C2H3O2
-(aq)
99%
![Page 15: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/15.jpg)
Group Work 5.1: Electrolytes in Solution
Compound Type #Ions inSolution
Compound
Type # Ions inSolution
HClO4 ACID 1 H +
1 ClO4-
Cu(ClO4)2
Ca(OH)2 Ca (NO3) 2
KHSO4 NH4H2PO4
Fe2(SO4)3 HBrO3
Ni(CH3CO2)2 SnCl4
![Page 16: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/16.jpg)
Double Replacement Reactions “go to completion”because collisions between some of the mixed anions and cations causes precipitates, molecules or gases to form, removing ions from solution. Our first type of reaction between aqueous solutions containing electrolytes involves forming a precipitatewhen the solutions are mixed.
This type of reaction goes to completion because ions are removed from solution as an insoluble precipitate.
![Page 17: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/17.jpg)
AB(aq) + CD(aq) AD(s) + CB(aq)
[A+(aq) + B- (aq)] + [C+
(aq) + D- (aq)] AD(s) + [C+(aq) + B- (aq)]
Reactions in Aqueous Solutions #1: Precipitation reactions
“salt A(aq) + salt B (aq) salt C (s) + salt D (aq)”
![Page 18: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/18.jpg)
NaCl(aq) + AgNO3(aq) AgCl(s) + NaNO3 (aq)
Na +Cl -
Na +Cl -
Na +
Na +
Cl -
Cl - Ag +
Ag +NO 3
-
NO 3-
NO 3-
NO 3-
Ag +
Ag +
AgCl AgClAgCl
AgCl
Na +
Na +
Na +
Na +
NO 3-
NO 3-
NO 3-
NO 3-
+
![Page 19: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/19.jpg)
Net Ionic Equations
• we prepare a “total ionic equation” in which all soluble electrolytes are representing as separate ions
• we cancel out any ion present on both sides of the equation
• the final result is called the “net ionic equation”.
We will practice this procedure as we go through thevarious types of double replacement reactions.
When we finish writing and balancing a double replacement reaction, we go several steps further:
![Page 20: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/20.jpg)
AB(aq) + CD(aq) AD(s) + CB(aq)
[A+(aq) + B- (aq)] + [C+
(aq) + D- (aq)] AD(s) + [C+(aq) + B- (aq)]
A+(aq) + D- (aq) AD(s)
Total balanced equation:
Total Ionic Equation:
Net Ionic Equation:
![Page 21: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/21.jpg)
NaCl(aq) + AgNO3(aq) AgCl(s) + NaNO3 (aq)
Na+ (aq) + Cl- (aq) + Ag+(aq) + NO3- (aq)
AgCl(s) + Na+ (aq) + NO3- (aq)
Ag+(aq) + Cl- (aq) AgCl(s)
Total equation:
Total Ionic Equation:
Net Ionic Equation:
![Page 22: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/22.jpg)
Acids: Mostly water soluble, commercially available in water solution
Salts and Bases: if both cation and anion are large insize and small in charge, ( +1,- 1), it is probably soluble in H2O.
Checkout following tables ...
SOLUBILITY OF “Strong Electrolytes” IN WATER
To predict when a precipitate will form, we need toknow some solubility guidelines:
![Page 23: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/23.jpg)
The Electrolyte is Usually Water Soluble if:
THE CATION IS:
• Na+
• K+
• NH4+
Always!
OR THE ANION IS*:• Cl-, Br-, I-
• ClO4-, ClO3
-
• NO3-
• SO42-
• CH3CO2-
*Mostly.....
![Page 24: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/24.jpg)
There are a few notable exceptions to thesolubility guide on the last slide, principally theones noted below, which you should be aware of:
Insoluble in Water:
AgCl, PbI2
BaSO4
![Page 25: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/25.jpg)
Group Work 5.2: SOLUBILITY WORKSHEET #1
Formula Name H2O Soluble?FeCO3
K2CO3
(NH4)3PO4
Co3(PO4)2
Mg(NO3)2
AgCl
CuI2
Cr2(SO4)3
![Page 26: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/26.jpg)
GROUP WORK 5.3: SOLUBILITY WORKSHEET #2
Bi(ClO4)3Ag Br
CdSO4
Zn(NO3)2
Ni(NO3)2
KMnO4
BaSO4
Al2O3
Mg3N2
Name H2O Soluble?
![Page 27: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/27.jpg)
Reactions in Aqueous Solutions #1 Precipitation Reactions
This type of reaction goes to completion if and only if any recombination of the reactant ions producesan insoluble precipitate.
Let’s Consider two possible reaction sequences:
K2SO4 (aq) + (NH4)3PO4 (aq)---> ?
CuSO4 (aq) + (NH4)3PO4 (aq)---> ?
![Page 28: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/28.jpg)
K2SO4 (aq) + (NH4)3PO4 (aq)---> ?
Step One: Write out the four reactant ions,decide if any combination is insoluble:
Cations: Anions:
K+ (no ppt) SO42- (usually soluble)
NH4+ (no ppt) PO4
3- (ppt???)
Decision: No cation to precipitate with thephosphate ion, therefore, no reaction!
K2SO4 (aq) + (NH4)3PO4 (aq) ---> NR, no reaction
![Page 29: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/29.jpg)
CuSO4 (aq) + (NH4)3PO4 (aq)---> ?
Step One. Write out each reactant ion. Decide if any combination of ions will produce a precipitate: Cations: Anions:
Cu2+(ppt???) SO42- (usually soluble)
NH4+ (no ppt) PO4
3- (ppt???)
Decision: The copper(II) ion will form an insolubleprecipitate with the phosphate ion and therefore reaction will occur.
![Page 30: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/30.jpg)
Step Two: since reaction will occur to form insolublecopper(II) phosphate, determine the correct formula for the products.
Cu3(PO4)2(NH4)2SO4
Charge per ion: 2+ 3- 1+ 2-
Total Charge: 6+ 6- 2+ 2-
Cu2+ (PO4)3- ---> Cu3(PO4)2
(NH4)+ + (SO4)2- ---> (NH4)2SO4
SMART ACTION: DOUBLE CHECK YOUR FORMULAS!
![Page 31: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/31.jpg)
[3 Cu2+
(aq) + 3 SO4
2- (aq) ] + [6 NH4
+ (aq) + 2 PO4
3- (aq) ]
---> Cu3(PO4)2 (s) + [6 NH4+
(aq) + 3 SO42-
(aq) ]
Step Three: Do a total balanced equation:
3CuSO4 (aq) + 2(NH4)3PO4 (aq)
---> Cu3(PO4)2 (s) + 3 (NH4)2SO4 (aq)
Step Four: Do a total ionic equation, showing the actual species involved in solution:
![Page 32: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/32.jpg)
Step Five: Prepare a “net ionic equation” for this reaction, by eliminating any ion which appears on both sides of the equation,
A “SPECTATOR ION” :
3Cu2+ (aq)
+ 3SO42-
(aq) + 6NH4+
(aq) + 2 PO43-
(aq)
---> Cu3(PO4)2 (s) + 6NH4+
(aq) + 3SO42-
(aq)
NET IONIC EQUATION
3Cu2+ (aq)
+ 2 PO43-
(aq) ---> Cu3(PO4)2 (s)
![Page 33: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/33.jpg)
a) Na2CO3 (aq) + Al(NO3)3 ( aq) ---> ?b) K2CO3 (aq) + NH4NO3 (aq) ---> ?c) CrCl3 (aq) + K3PO4 (aq) --->?
For reaction(s) which “go to completion”:
2. Complete Product Formulas 3. Balance Equation4. Do Total Ionic Equation5. Do Net Ionic Equation
1. Decide which of above is NR (“no reaction”) by writing down all four ions involved
GROUP WORK 5.4: NET IONIC EQUATION
![Page 34: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/34.jpg)
Reactions in Aqueous Solutions: #2 Acid/Base Reactions
These reactions are double replacement, like the precipitation reactions we just studied. However,in this case, the reaction will ALWAYS go to completion because an un-ionized molecule, water, is formed. In both cases (precipitation; acid/base), the removal of ions from solution causes the reaction to go to completion...
Acid + Base ---> Salt + H2O
![Page 35: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/35.jpg)
ACIDS are defined in the most common (“Arrhenius”) system as substances which increase the H+ ion concentration when dissolved in water.
ACIDS may be recognized by the convention of writing H first in the formula of the compound; in general the formula contains H plus some cation except OH-.
Strong acids are 100% ionized in aqueous solutions and therefore “strong electrolytes”;
Weak Acids are generally <5% ionized in aqueous solutions and therefore “weak electrolytes”.
![Page 36: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/36.jpg)
Let’s consider names and formulas of common acids and bases which we meet in these reactions:
COMMON STRONG ACIDS:
HCl Hydrochloric acid
HBr Hydrobromic acid
HI Hydroiodic Acid
HNO3 Nitric Acid
HClO4 Perchloric Acid
H2SO4 Sulfuric Acid
Notenames:learn!
![Page 37: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/37.jpg)
COMMON WEAK ACIDS:*
H3PO4 Phosphoric Acid
H2CO3 Carbonic Acid
H2SO3 Sulfurous Acid
H2S Hydrosulfuric Acid
CH3CO2H Acetic Acid
* and many, many more.....
Learn Names,Recognize!
![Page 38: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/38.jpg)
BASES are defined in the Arrhenius system assubstances which increase the OH- ion concentration when dissolved in water.
BASES may be recognized as the combination of some metal or ammonium cation plus the OH- orO2- anion. The list of strong bases in water is severely limitedby the lack of solubility of most metal hydroxidesand oxides in water; all of these compoundsdo however react with acids to yield salts plus water.
![Page 39: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/39.jpg)
COMMON STRONG BASES
(LiOH Lithium Hydroxide)
NaOH Sodium Hydroxide
KOH Potassium Hydroxide
These are the only bases classified as strongelectrolytes because they are the only onessoluble in water. Other metal hydroxides and oxides are basic but insoluble.
![Page 40: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/40.jpg)
AMMONIA AS A WEAK BASE
As we have seen earlier:
NH3(g) + H2O ---> NH4+
(aq) + OH-(aq)
<-------------
99% 1%
This reaction with water produces a small numberof hydroxide ions in water solution, so aqueous ammonia is considered a weak base.
![Page 41: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/41.jpg)
SALTS IN AQUEOUS SOLUTION
All common salts which are water soluble arestrong electrolytes, 100% ionized in the aqueoussolution.
Salts can be recognized by their formulas, in which a metal or ammonium cation is written first and some anion second.
![Page 42: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/42.jpg)
NET IONIC EQUATIONS FOR ACID BASE REACTIONS
NOTE: If any acid and base are mixed together and at least one of them is in aqueous solution ,a reaction will always occur and go quickly to completion: the formation of the water moleculefrom the H+ of the acid and the OH- or O2- of thebase is very energy releasing and exothermic.
Acid + Base -----> Salt + H2O
Both strong and weak types react in this fashion!
![Page 43: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/43.jpg)
Net Ionic Equations for Acid /Base Reactions
1. Recognize that all reactions between acids and bases go to completion if at least one of them is in aqueous solution.
2. Decide on formula of salt product to accompany the H2O formed.
3. Balance the Equation4. Do a Total Ionic Equation5. Do a Net Ionic Equation
![Page 44: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/44.jpg)
2. Formulas of products: Combine the H and OH to form water, and the leftover ions to make the salt:
Cl- + K+ ----> KCl
4. Total Ionic Equation:
H+(aq) + Cl-
(aq) + K+ (aq) + OH-
(aq)
-----> H2O(l) + K+ (aq) + Cl-
(aq)
3. Balance the equation (ok as written):
HCl(aq) + KOH(aq) ---> HOH(l) + KCl (aq)
Reaction #1 HCl(aq) + KOH(aq) ---> ? ---> 1. H2O + salt
![Page 45: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/45.jpg)
5. IDENTIFY THE SPECTATORS:
H+ (aq) + Cl- (aq) + K+ (aq) + OH- (aq) -----> H2O(l) + K+ (aq) + Cl- (aq)
NET IONIC EQUATION:
H+ (aq) + OH- (aq) -----> H2O(l)
![Page 46: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/46.jpg)
1.H3PO4 (aq) + NaOH(aq) ---> ? -----> H2O + salt
2. Predict the salt formula and complete equation:
( PO4)3- + Na+ ---> Na3PO4
H3PO4 (aq) + NaOH(aq) ---> H2O(l) + Na3PO4(aq)
3. balance the equation:
H3PO4 (aq) + 3 NaOH(aq) --->3H2O(l) + Na3PO4(aq)
Now, another:
![Page 47: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/47.jpg)
H3PO4 (aq) + 3 NaOH(aq) --->3H2O(l) + Na3PO4(aq)
4. Convert into total ionic equation, noting that thephosphoric acid is a weak electrolyte, about 99%molecular, so we do not show its ions in water:
H3PO4 (aq) + 3 Na+(aq) + 3 OH- (aq) --->
3H2O(l) + 3 Na+(aq) + PO43-(aq)
5. NET IONIC EQUATION:
H3PO4 (aq) + 3 OH- (aq) ---> 3H2O(l) + PO43-(aq)
![Page 48: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/48.jpg)
Group Work 5.5
Do Net Ionic Equations for the following:
1. Fe2O3 (s) + HCl(aq) ---> ?
2. H2CO3 (aq) + KOH (aq) --->?
3. H2SO4 (aq) + Ba(OH)2 (s) -----> ?
![Page 49: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/49.jpg)
5.5 Gas-Forming Reactions
Finish up on Net Ionic Equations: third type of double replacement reactions:
1. Precipitation Reactions2. Acid/Base Reactions3. Gas Formation Reactions
Two types considered:
Sulfide salt + acid -----> salt + H2S(g)
Carbonate salt + acid -----> salt + CO2(g) + H2O
Formation of gaseous product causes reaction completion
![Page 50: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/50.jpg)
Sulfide Salt + Acid
2 K+(aq) + S2-
(aq) + 2 H+2 (aq) + SO4
2- (aq) ----->
2 K+(aq) + SO4
2- (aq) + H2S(g)
2 H+2 (aq) + S2-
(aq)-----> H2S(g)
Sulfide salt + acid ----> new salt + H2S(g)
K2S(aq) + H2SO4 (aq) -----> K2SO4 (aq) + H2S(g)
![Page 51: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/51.jpg)
Carbonate Salt plus Acid
Carbonate salt + acid -----> new salt + CO2(g) + H2O
CuCO3(s) + 2 HCl(aq) -----> CuCl2(aq) + [ H2CO3(aq)]
[ H2CO3(aq)] -----> H2O(l) + CO2(g)
CuCO3(s) + 2 HCl(aq) -----> CuCl2(aq) + H2O(l) + CO2(g)
![Page 52: TOPIC V: Ions in Aqueous Solutions LECTURE SLIDES: Precipitation Reactions Solubility : Acids, Bases, Salts Net Ionic Equations Acid/Base Reactions Gas.](https://reader030.fdocuments.us/reader030/viewer/2022032704/56649d545503460f94a31081/html5/thumbnails/52.jpg)
CuCO3(s) + 2 H+ (aq) + 2 Cl- (aq)
-----> Cu2+ (aq) + 2 Cl- (aq) + H2O(l) + CO2(g)
CuCO3(s) + 2 H+ (aq) -----> Cu2+ (aq) + H2O(l) + CO2(g)